Translating device



Oct. 3; 1939. o. M DUNNING 2,174,692

TRANSLATING DEVICE Filed April 9, 1937 \INVENATOR OrvzlleMDunnmg BY fTTORNEY Patented Oct. 3 1939 UNE-ED sis TRANSLATING DEVICE ApplicationApril 9, 1937,'Serial No. 135,885

13 Claims.

This invention relates to translating devices, and more particularly todevices for translating acoustic or electric oscillations intomechanical oscillations, or vice versa. It is a broad object to provideimproved such devices.

While not necessarily in all aspects limited thereto, the invention isof particular utility with devices wherein as active elements there areemployed piezo-electric units, especially of the bending type. It is anobject to provide improved translating devices employing such units.

A difficulty commonly encountered in the use of such units intranslating devices is their fragility. It is an object of the inventionto provide an improved translating device construction wherein thepiezo-electric or other active unit is better proof against breakage anddamage than heretofore.

The difiiculty of fragility is especially common in connection withtranslating devices such as phonographic recorders, Wherewith there is acontinual necessity for eifecting, terminating and altering themechanical contact of the device with a record, which further may be inmotion,

, and for generally frequent handling of the device.

It is a particular object of my invention to provide a more sturdyrecorder.

A broader object is the provision of a generally improved recorder andconstruction therefor.

Other and allied objects will more fully appear from the followingdescription and the appended claims.

In the drawing and description I have chosen to illustrate and describemy invention in connection with a translating device adapted for use asa recorder and comprising as an active element a piezo-electric unit ofthe bending type as abovementioned; this is, however, intended asexemplary only and not as comprehensive of the various purposes andcomponents for and with which my invention may be carried out, as willbe obvious as the description proceeds.

In the description reference is had to the accompanying drawing, ofwhich:

Figure 1 is a vertical cross-sectional view of a recorder embodying myinvention;

Figure 2 is a bottom plan view of the recorder of Figure 1, the line l lin Figure 2 indicating the vertical plane upon which Figure 1 is taken;and

Figure 3 is a perspective view of the same recorder, showing the mainframe and therewith associated components removed and drawn slightlyaway from its pivots, for the sake of clearer illustration.

In carrying out my invention I movably support, relative to a load (forexample, a mechanical load in the form of a record to be cut orimpressed with sound-representing undulations), a system vibratable inaccordance with oscillations thereto supplied (for example, acousticoscillations, or electric oscillations translated therefrom and suitablyamplified). The vibratable system in the illustrated recorder is ofcantilever form, and comprises the piezo-electric unit 'I the stylus 8secured to the right-shown extremity thereof by means of the mounting 8(in which the stylus is partially imbedded and which in turn is cementedabout the unit extremity), and the unit base 2 of U-shapedcross-section, whichmay be of metal and in which the unit I is'insulatedly cemented at its extremity opposite the stylus. Thepiezo-electric unit I may be of the so-Called bi-morph form-wherein twocrystals are secured facc-to-face, electrically arranged forsimultaneous voltage application, and further arranged so that onecontracts longitudinally as the other expands (and vice versa) to resultin a transverse (e. g., up-and-down) bending. The stylus 8 is shownengaging the surface of a record R, the stylus and record being of anymutually appropriate forms, and the record being for example arrangedfor continuous movement by means not necessary to show.

It will be obvious that the undulations in the record for the creationof which the illustrated system is arranged are vertical, although nolimitation of broader aspects thereto is intended. In prior co-pen'dingapplications of mine, for example Serial No. 701,247, filed December 6,1933 (on which Patent No. 2,106,051 has since been granted), I haveshown and claimed arrangements of the character of the illustrated oneas so far de scribed. But in those structures the necessary bias of thevibratable system-more specifically, of the stylus-against the load .orrecord has been wholly or principally provided by mass or otherforce-applying means integral with or influencing the unit base;accordingly this force has been transmitted wholly or principallythrough the unit longitudinally. This construction imparts a steadybending strain on the unit throughout its length whenever the stylus isin position engaging a. record; this force is suddenly applied andrelieved upon stylus placement upon and removal from the record, callingupon the unit to withstand abrupt strain changes and excessive impactivestrains; and these undesirable influences are augmented by the observedlikelihood of unskilled persons pressing upon and otherwise handling thestylus, with corresponding strain production through the unit. In short,an excessive tendency to breakage of the unit exists with such astructure, at least in the absence of certain special measures anynecessity for which is obviated by the present invention.

The vibratable system has of course a principal vibratable portion (e.g., its stylus extremity) and a portion which tends to resist vibration(e. g., the base 2, in view of its mass). According to this invention Ipreferably by-pass the intervening or most fragile central portion ofthe system with the necessary force-applying means, for exampleconnecting such means instead directly with the principal vibratableportion, or stylus extremity of the unit. I also may, and preferably doso apportion and so movably mount the base 2 as to minimize anysignificant contribution by its mass to record-ward stylus bias, and itwill be understood that the mass of a typical bending unit 5 is verylow. Accordingly the force-applying means which I employ to operatedirectly on the stylus extremity of the unit may supply the principalportion of a desired bias, and of this principal portion no part need betransmitted longitudinally through the vibratable system;

The force-applying means may be of any desired form, subject to thequalification that the vibration of the vibratable system portion shallnot be thereby seriously interfered with; I have preferred and haveiilustrated the force-applying means as comprising a resilient member orspring terminally associated with the stylus extremity of the unit.While the other terminal of this spring may be held stationary inposition to create a suitable average compression in the spring, I havepreferred to utilize the spring only as a coupling part of theforce-applying means, the force ultimately being derived from a primaryforce-supplying part such asa movably supported and suitably positionedmass. An optional feature of my invention is the movable' supporting orpivoting of the vibratable system (e, g., of unit base 2) to a portion(preferably of low moment) of this mass. Having so generalized some ofthe aspects of my invention, I may refer back to the drawing inconnection with a more detailed description.

The mass which I preferably employ as a forcesupplying means is seen asa generally horizontal and relatively heavy main plate or frame 3, withbent-down vertical ears 3 along its sides at its left-shown extremity.By brackets 5 secured to the top of the frame 3 the latter'is pivotedtomeans provided to the left of this extremity, as hereinafter is moredetailedly described. The unit base 2 is seen pivoted between the ears3' by the adjustable pivot screws 5 through the latter. The frame 3extends rightwardly over the unit i to terminate a little beyond itsstylus extremity; and between the stylus mounting ti and the frame 3will be seen, in the form of spring 9, the resilient means which couplesthe vibratable system to the frame 3, and which with the latter makes upthe force-applying means. The spring 9 is preferably (though, in view ofits normal placement in compression, not necessarily) secured at itsrespective terminals.

It Will be understood that upon the application across the electricalterminals of the unit l (hereinafter more specifically mentioned) of asuitable voltage, for example sound-representing, the unit will vibratevertically in correspondence therewith and at amplitude increasing alongthe length of the unit up to and including its stylus extremity;

the stylus accordingly is moved up and down to create a likewisecorresponding sound track or undulating groove in the meanwhile-movedrecord. In view of the mass of the unit base 2 little of the vibratoryforce is dissipated in oscillatory rotation thereof about its pivot. Inview of the high mass of frame 3 no appreciable vibration is dissipatedin it. In view of the substantially pure compliance nature of the member(spring 9) which is immediately coupled to the principal vibratablesystem portion, the only impediment to vibration of the latter offeredat this extremity by this construction is by the stiffness of thisspring-which is simply additive to the necessarily present unitstifiness and effective record stiffness, and may in typical cases be anegligible fraction of these. The vibratory action of the vibratablesystem amounts to a modulation of the compression of spring 9, and ofthe steady bias imparted to the stylus principally through that spring,The mass of plate 3 will of course be fixed at whatever value produces adesired eifect of the stylus on the record in any given case; thecompliance of spring 9 is desirably made as great consistent withreasonably small change of its length between no-compression andnormalcompression conditions.

It will be obvious that now the vibratable system has been practicallywholly relieved of the requirement of longitudinal force transmissionand from attendant strains, abrupt changes of strain, etc. producedeither by any intended use of the device or by any other pressure frombeneath the stylus. Because of the considerations detailed in thepreceding paragraph, however, there need be experienced no substantialchange of efiiciency or performance throughout the desired frequencyrangefor example, of audio frequencies-from simpler systems withoutthese salient advantages.

The description of the illustrated recorder may be completed byattention to the pivoting of the main frame (through brackets 5), theelectrical connections to the'unit I, etc. The brackets 5 are providedwith the extending arms 5 through each arm near its extremity is passeda respective rivet l8 insulated from the arm by insulating bushings H.Held secure under each rivet, next to a respective bushing H, is arespective soldering lug ii; the electrical leads I from unit I are ledinsulatedly through the unit base 2 and connected to the respectivelugs-so that the latter, or the rivets if! in contact therewithrespectively, become in effect the terminals of the unit.

The means to which the frame 3 is pivoted may be a vertical memberlwhich for example may be secured to a travelling carriage, notnecessary to show; for rendering the track of the stylus on the rotatingrecord a spiral one. On either side of the member ID are spacedly andinsulatedly secured, as by suitable horizontal collar bushings I3 thevertical lug members ll; each of these may carry near its bottomextremity an outwardly extending horizontal pivot 12. These pivots areadapted to engage the centers of the respective insulated rivets iii inarms abovementioned, and thus both to pivot the frame 3 and to makepossible electrical connections to the unit I simply by connections tothe respective unpivoted lug members I l--for example by means of thescrews l i in the folded-over top extremities i l of these lug members,The pressure against the pivots 52 of the arms 5 may be adjusted as bythe screw i5 clearingly passed through one of the arms and threaded intothe other, at intermediate regions along the arms.

A casing 4, suitable apertured for outward extension of the stylusmounting 8', may be provided to close substantially the end, sides andbottom of the device for appearance, dust elimination, and prevention ofdirect impact against the unit I. This casing also, in the event ofnon-securing of the extremities of spring 9, serves to prevent theexcessive downward swinging of the unit I upon lifting of the frame 3 todisengage the stylus from the record. The bottom of this casing has beenomitted from the bottom plan View of Figure 2, for the sake of clearerillustration.

A specific embodiment of my invention having been so described, it willbe obvious to those skilled in the art that wide modifications in thecomponents and purposes of the device may be made within the spirit ofthe invention. For example, it is apparent that certain of thehereinbefore stated objects of the invention will be attained where thedesired bias of the stylus toward the record or at least the principalportion of such bias is derived from the vibratable system itself or anyforce-supplying means other than the plate or frame 3, or where anappreciable or the major portion of said bias is transmitted through thevibratable system. I accordingly intend no unnecessary limitations byvirtue of the specific characteristics of this embodiment; rather, inthe appended claims I undertake to express the scope of my inventionbroadly, limited only by the state of the art.

I claim:

1. In a translating device, a frame movably mounted adjacent a load andbiased theretoward; a piezo-electric bending unit having a portionmovably mounted to said frame; and means for coupling with said frame,for bias toward the load by said frame, a portion of said unit remotefrom said mounted portion.

2. In a translating device, a bending unit adapted to translate otheroscillatory energy into oscillatory bending of the unit and vice versa,freely mounted in a first portion thereof for movement of a secondportion thereof toward and away from a load; and means resilientlyassociated with said second portion for biasing the same toward theload.

3. In a translating device, a bending unit adapted to translate otheroscillatory energy into oscillatory bending of the unit and vice versa,freely mounted in a first portion thereof for movement of a secondportion thereof toward and away from a load; and means immediatelyassociated with and influencing said second portion for biasing the sametoward the load.

4. In a translating device, a bending unit adapted to translate otheroscillatory energy into oscillatory bending of the unit and vice versa,freely mounted in a first portion thereof for movement of a secondportion thereof toward and away from a load; and means by-passing atleast a portion of said unit between said first and second portions forbiasing said second portion to ward the load.

5. In a translating device, a bending unit adapted to translate otheroscillatory energy into oscillatory bending of the unit and vice versa,freely mounted in a first portion thereof for movement of a secondportion thereof toward and away from a load; means distinct from saidunit for supplying a force toward the load; and means resilientlycoupling said second unit portion with said force-supplying means forbias toward the load.

6. In a translating device, a frame movably mounted adjacent a load andbiased theretoward; a bending unit adapted to translate otheroscillatory energy into oscillatory bending of the unit and vice versa,having a portion freely mounted to said frame; and means for couplingwith said frame, for bias toward the load, a portion of said unit remotefrom said mounted portion.

7. In a. translating device, a cantilever system comprising apiezo-ele'ctric bending unit supported at its base for movement of itsextremity and for bending toward and away from a load, and meansresiliently associated with said extremity for biasing the same towardthe load.

8. In a translating device, a cantilever system comprising apiezo-electric bending unit supported at its base for movement of itsextremity and for bending toward and away from a load, and meansimmediately associated with and influencing said extremity for biasingthe same to" ward the load.

9.'In a translating device, a cantilever system comprising apiezo-electric bending unit pivoted at its base for movement of itsextremity toward a load, and means by-passing at least the centralportion of said unit for biasing said extremity toward the load.

10. In a translating device, a cantilever system comprising apiezo-electri'c bending unit supported at its base for movement of itsextremity and for bending toward and away from a load; means distinctfrom said system for supplying a force toward the load; and meansimmediately associated with said extremity for coupling the the samewith said force-supplying means.

11. In a translating device, a cantilever system comprising apiezo-electric bending unit having a vibratable extremity adjacent aload, and supported at its base for movement of said extremity and forbending toward and away from the load; a mass also supported adjacentand for movement toward the load; and means resiliently coupling saidextremity with said mass for bias toward the load.

12. In a phonographic recorder adapted for cooperation with a recordmoved relative thereto, a frame movably mounted adjacent the record andbiased theretoward; a piezo-electric bending unit having a portionmovably mounted to said frame; a record-engaging stylus carried by aportion of said unit remote from said mounted portion; and means forcoupling said remote unit portion with said frame for bias of saidstylus against the record.

13. In a phonographic recorder adapted for cooperation with a recordmoved relative thereto, a frame movably mounted adjacent the record andbiased theretoward; a bending unit adapted to translate otheroscillatory energy into oscillatory bending of the unit, having aportion freely mounted to said frame; a record-engaging stylus carriedby a portion of said unit remote from said mounted portion; and meansfor coupling said remote unit portion with said frame for bias of saidstylus against the record.

ORVILLE M. DUNNING.

